yap unfortunately - if you submit your form - the ext form makes an ajax request and waits for a success message made by the server. If you want a standard form submit behaviour you have to set standardSubmit:true.

Alternatively as said in the answer above you can redirect manually with "document.location.href" in the success callback function of your js-submit function (so you have to send a success-object to the client in your server's method instead of making a redirect).